The present invention relates to a process and an apparatus for the regulation of the fuel-air mixture delivered to the combustion chambers of an internal combustion engine, through the admission of auxiliary air in correspondence with the aspirated fresh air quantity. The auxiliary air is admitted via an air-bypass line around a measuring member measuring the fresh air quantity.
An apparatus for the execution of such a process is disclosed in the DT-OS 24 31 046 (laid open German application). This application discloses a valve in an air-bypass line entering the suction tube of the intake manifold of the internal combustion engine downstream of the throttle flap which is actuated by the throughput dependent reduced pressure developed within a venturi in the suction tube to accomplish the allocation of the auxiliary air. This reduced pressure is modified by a valve actuated in correspondence with a signal from an oxygen measuring probe within the exhaust system of the internal combustion engine. However, only an additive modification of the auxiliary air admitted via the valve in the air bypass line can be achieved with this apparatus, which factor entails the disadvantage that the regulation works comparatively slowly, and also that its effect differs for differing operational regions of the internal combustion engine.